Andrea Nakano contributed to this report.

ANTIOCH (CBS SF/AP) — New details emerge regarding the death of a mentally ill Antioch Navy veteran after being restrained by police.

The Antioch Police Department Tuesday night released 911 tapes of the family’s cries for help. It’s a call to police Cassandra Collins regrets to this day. Her brother, Angelo Quinto was suffering a mental episode and acting aggressively towards their mother.

All she wanted was help but instead, she is grieving her brother’s death.

In a police released 911 recording, Cassandra Collins says, “My brother is being aggressive.”

That 911 call was made just two days before Christmas after eleven at night.

You can hear the terror in Cassandra Collins’ voice. She adds on the 911 call, “My mom can’t breathe. Stop it, stop it.”

Within minutes police arrive and help restrain 30-year-old Angelo Quinto. But family members want some answers to what happened next.

“In my view, there is no question or challenge to the right of them being at the house when they did but the question is what did they do?” said civil rights attorney John Burris, who is representing the family.

The Burris legal team re-enacted the events from that night. The family alleges officers had their knee on Quinto’s neck for minutes. Antioch Police though say they only had a knee on his shoulder blade for a few seconds during the handcuffing process.

During a Tuesday evening press conference, Antioch Chief Tammany Brooks described far different techniques than the Quinto family did.

“At no point, did any officer use a knee or other body parts to gain leverage or apply pressure to Angelo’s head, neck or throat which is outside of our policy and training,” Chief Brooks said.

Chief Brooks says the investigation, so far, shows no signs of injuries in connection with the struggle, no fractures to the skull or torso and no evidence of strangulation.

“At one point during the handcuffing, an officer did briefly — for a few seconds — have a knee across the back of Angelo’s shoulder blade,” said Brooks.

Police insist that move is something taught and approved by California police academies. They also say a medical examination of Quinto’s body did not show any fractures to his head, neck or the rest of his body.

Burris, though, says this is another case where officers lack the proper training to deal with a mental health crisis.

“Nothing is more horrifying to me that a mentally impaired person when’s a family calls for help and the help they get, the person winds up dead. That should not be the case here,” said Burris.

RELATED Family: Navy Vet Died After Antioch Police Officer Knelt On His Neck For 5 Minutes

The in-custody death made national headlines.

Last week, Cassandra Quinto-Collins, Quinto’s mother, gave her version of the arrest.

“He said ‘Please don’t kill me. Please don’t kill me,’ as they were putting him on the ground. They handcuffed him and one officer put his knee on the back of his neck the whole time I was in the room,” said Quinto-Collins.

According to their attorney John Burris, Quinto’s family is still questioning if police used excessive force on their son.

“I trusted the police because I thought they knew what they were doing but he was actually passive and visibly not dangerous or a threat so, it was absolutely unnecessary what they did to him,” she said.

A video recorded by Quinto-Collins shows her son listless, with a bloodied face and his hands cuffed behind his back. She said she began recording after seeing her son’s eyes were rolled up in his head.

The family filed a legal claim against the Antioch Police Department earlier in February, which gives the department 45 days to respond. After that time has elapsed, the family will file a federal lawsuit, said Burris.

“I refer to it as the George Floyd technique. That’s what snuffed the life out of him and that cannot be a lawful technique,” Burris said. “We see not only violations of his civil rights but also violations against the rights of his mother and sister’s, who saw what happened to him.”

© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.